They're the same word: favorite is the American spelling, favourite is the British spelling. If you're writing for a UK, Irish, Australian or Canadian audience, use favourite; for a US audience, use favorite. A quick memory hook: favourite keeps the u, just like colour and honour.
The core difference
Favorite and favourite are identical in meaning — the spelling depends purely on which English you're writing.
- favorite — American spelling: Pizza is my favorite food.
- favourite — British spelling: Pizza is my favourite food.
How to tell them apart
There's no difference in meaning to remember here, only a difference in dialect. Both spellings trace back to the 16th-century French favorit, itself from Latin favor ("goodwill"). British English later added the -our ending you also see in colour and honour, while American English kept closer to the shorter -or form.
The mix-up usually shows up when switching between a US style guide and a UK one, or when spell-check flags one version as wrong simply because it's set to the other region. Pick one spelling and stay consistent throughout a document — mixing favorite and favourite in the same piece of writing looks like an error even though both are correct somewhere.
